Method of making nitrous oxide



Filed may 7; i920 M P MILLER ET im METHOD OFMAKING NH'MUS 931W' staru .,i la

tall

A MAX P. MILLER AND MAURCE F. ROCHE,

0F CLEVELAND, OHM), ASSIGN'RS T0 'lili-IE PENNCX CHEMICAL COMPANY, 0F CLEVELAND. (7R10. A COREPORATIGN tilfill. i

METHD O'F MAKING NTROUS OXIDE.

Application filled i May 7,

T0 all whom t may concern:

Be it known that we, MAX P. MILLER and MAURICE F. ROCHE, both citizens of the United States, and residentsof Cleveland, county of Cuyahoga, and State of Ohio, have jointly invented a new and useful lmprovenient4 in Method of Making Nitrous Oxide. of which the following is a specification. the principle of theinvention being herein explained and the best mode in which we have contemplated applying that prin-- ciple, so as to distinguish it fromf other inventions.

The present invention, relating, as indicated, to a method of making nitrous oxide is designed toprovide an improved process for manufacturing this product which will permit vot" continuous `operation and of a continuous passage and treatment of the ma- .terial from the beginning to the end of the process.

It is customary 4in the manufacture of nitrous oxide' to rst treat ammonium hydroxide with nitric acid to produce ammonium nitrate and water.` vThe products of this reaction are then run into an evaporatv ing tank where the water `is evaporated, leaving the solid ammonium nitrate. This solid product is cooled and moved from the 4ve'vaporating tank and broken into particles of small size, after which it is charged linto a 4suitable kettle and strongly heated to break -up the ammonium nitrate with the" evolution of nitrous oxide gas. This method, which is the standard method yof producing nitrous oxide, involves a considerable delay because of the necessity for cool ing,` disintegrating and then `again heating the ammonium nitrate, and it is one object of the present invention to eliminate this unnecessary delay and expense, To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and par-v ticularly pointed out in the claims.'

The annexed drawing and the following description set forth in detail certain means and one mode of carrying .out the invention. such disclosed means and mode illustrating, however, but one of various ways in which 'the'principle of the invention may be used.

In said annexed drawing The single figure there appearing is a diagrammatic view illustrating the various apparatus necessary for carrying out our im 1920. Serial No. 379,497'.

Vproved method, together with the various parts of the appatric acid. are charged into a reaction chamber 1, where they are allowed to react with a formation of water and dissolved ammoniuinnitrate. After this reaction has taken place the reaction products are drawn od through a conduit 2 into an evaporating chamber 3. lThis chamber is heated by steam or other suitable fluid supplied through a conduit a. 1t passes through the jackets of the evaporator 3 and is then returned to the boiler. through a conduit 5, in which is a trap 6 for collecting the water of condensation and returning it to the boiler.

The reaction products are heated in the evaporator 3 until most. of the water has been evaporated and the' solution boiled down to the consistency of a thick syrup. The evaporated water is led away through a conduit 7 into a condenser 8. The syrupy residue is then run directly into a steam jacketed kettle 9 through a conduit 10 having a control valve 11 therein. The steam ing, these plates 13 passing between stationary plates or members 14. The shaft 12 may be driven by any suitable means, such as bevel gears 15 and 16, of which the gear 15 is on a shaft 17 driven by a pulley 18.

The heating means for heating both the evaporator and the steam jacketed kettle 9 consists of a boiler, indicated diagrammatically at 20, and connected to aisuperheater 21. From this superheater there extends a conduit22 leading to the upper part of the jacket 23 of the kettleA 9, while the steam is discharged from this jacket through a conduit 30 containing a trap 31, and leading to the conduit 4 which supplies the jacket of the evaporator 3. A regulating thermostat 33 is provided in a branch conduit 3ft leading from the conduit 22, this conduit 34 entering the kettle 9 and the thremostat 33 controlling a valve 35, which opens or closes the conduit 22, depending upon the lll@ temperature existing in the kettle 9. A pyrcineter control is also provided, there being a pyrometer 3? connected by conduits 38 and 39 to the 'conduit 22 and to the kettle 9, respectively. The pyrometer control enables the operator to follow the temperature in the kettle 9 and to thus maintain a close regulation of the steam that heats this kettle.

The nitrous oxide produced in the kettle 9 is carried through a conduit 40 to an acid collecting chamber 4l, and then through a conduit 42 to the usual Washing and scrubbing apparatus for purifying it. A sight 43 is introduced into the conduit 40 so that the operator may observe 'the mate. rials coming ott` from the kettle 9.

Our improved method involves the trans'- 'ferring of the syrupy ammonium nitrate directly to the steam jacketcd kettle 9 While the liquid is still at high temperature. `When so transferred, and before the liquid is cooled it is further strongly heated by the superheated steam in the jackets 23 to a temperature of about 225 C. and there is usually a variation of not lto exceed above and below this temperature. The first result of this further heating is to volatilize the slight amount of Water remaining, after which the ammonium nitrate is broken up with the evolution of the desired nitrous oxide gas, which is suitably -collected after having been Washedand otherwise puriiied in therusu'al manner. ln this manner we are able to reducethe heating cost of the production of nitrous oxide by approximately one-half, While there is no delay at any stage of the process, ,nor is it necessary to mechanically break up the crystallized ammonium nitrate as is the case in 'current practice.

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the steps or mechanism herein disclosed, provided the means stated byany of the following claims or the equivalent of such stated means by employed.

We therefore particularly point ont and rating the Water formed by such reaction,

heating the hot ammonium nitrate while still hot from such evaporating While agitating vthe same and collecting the nitrous oxide evolved.

'3. In a method of making nitrous oxide, the steps which consist in treating ammonium hydroxide `with nitric acid, concentrating the solution to thc consistency of a syrup. heating such concentrated ammonium nitrate while still hot from such concentrating While agitating the same and collectingthe nitrous oxide evolved.

4. In a method of making nitrous oxide` the steps which consist in treating ammonium hydroxide with nitric acid, concentrating the solution to the consistency of a syrup by heating, heating such concentrated ammonium nitrate to a temperature of approximately 225 degrees C. While still hot from such concentrating While continuously agitating the same, an then collecting the nitrous oxide evolved.

Signed by us, this 29th day ot April, 19.20.

' MAX. P. MILLER..

NLAURICE F. ROCHE. 

